Manufacture of steam-boilers.



H. H. TRACY & H. E. BOYRIE.

MANUFACTURE OF STEAM BOILERS.

APPLICATION FILED MAY 2, 1911.

1,025,337. Pat ented m 7, 1912.

al I d2 }w K i J a! J 'I 1 I G i I l O G (D H Q m M/OMOT D UNITED STATESPALIENT OFFICE.

HAYDEN HOMER TRACY, OF BERKELEY, AND HARRY EUGENE BOYRIE, OF SANFRANCISCO, CALIFORNIA.

MANUFACTURE OF STEAM-BOILERS.

To all whom it may concern."

Be it known that we, HAYDEN HOMER TRACY, a citizen of the United States,and resident of the city of Berkeley, in the county of Alameda and Stateof California, and HARRY EUGENE BoYRIE, a citizen of the United States,and resident of the city of San Francisco, in the county of SanFrancisco and State of California, have jointly invented a certain newand useful Improvement in the Manufacture of Steam-Boilers, of which thefollowing is a specification.

This invention relates generally to cylindrical boilers, or drums, ofsheet metal designed for water and steam circulation,and particularly tothose boilers or drums where the main joints are longitudinal, and inwhich a plurality of perforations must be made close together at someparticular por tion or portions of the circumference for the receptionof tubes.

The main objects of the improvement are to insure the maximum economy inmaterial and labor, combined with the greatest efficiency in strengthand durability, as well as convenience in manufacture and use.

A special purpose is to compensate for the weakening of the boiler ordrum caused by the tube-openings at those parts which so often have tosustain the greatest load or strain. I

A further object is to present an integral structure with anevenly-continuous inner surface in place of those constructions wherelapped seams or edges joined by rivets, are employed, with the necessaryobjection that the radius of the interior face of such styles of boilersis not uniform, and difliculty in consequence is experienced in fittingthe required cylindrically-flanged heads or caps thereto, as in the caseof steam and water drums for water-tube boilers.

A further and important object of the invention is to economize inweight of metal, it having been demonstrated that by doing away withoverlapped meeting edges, and butt-joints, and the rivets heretoforefound necessary in all of such structures, a saving in weight and costof material alone of about one-half is effected.

To these ends, the invention contemplates-as an essential featurethewelding of the meeting edges of the metal composing the boiler or drumshell, by any of the approved methods, or processes, such as bySpecification of Letters Patent.

Application filed May 2, 1911.

Patented May *7, 1912.

Serial No. 624,571.

electricity, or by acetylene or other gases capable of producing intensewelding heat. (From this feature alone, the weakening of the structurecaused by drilling for rivets at or near the seams, which invariablyresults from the practices now in vogue, is entirely obviated, whetherthe lapped joints have been narrow or otherwise, or whether they aresingle, double or triple riveted in any of the forms now commonly used.)(It may be further explained that it is impossible to make a rivetedjoint with an eiiiciency of 100 per cent, owing to the loss of that partof the sheet body where the rivet holes have to be made. A welded joint,

however, we have found, can be made with.

an efliciency exceeding 100 per cent, as it can be built up thicker thanthe main sheet, and the joint then becomes one of the strongest parts ofthe structure instead of the weakest.)

Briefly speaking, the present invention consists in a structureinvolving a metal cylinder made from a plate with the meeting edgesabutting one against th other, and welded, brazed, or fused in S1101manner as to present a uniform continuous cylindrical surfaceinteriorly, and at the same time be homogeneous exteriorly of thecircumference,-such plate, however, being of two thicknesses or gages ofmaterial, the greater weight or thickness coming at the point-or at suchportion of the circumferencewhere such metal may have to be drilled orperforated for the reception of water or steam tubes.

For more complete comprehension of the invention, reference may be hadto the accompanying drawings forming part of this specification.

Figure l is a cross-section of a boiler or drum constructed according toour invention. Fig. 2 is a longitudinal vertical section. Fig. 3 is adiagrammatic plan of the sheet from which the improved cylinder ispreferably made.

In said drawings similar letters of reference indicate like parts.

In carrying out our invention, we prefer to form the boiler plate A byrolling according to any approved method, it being essential that thesheet be of at least two different thicknesses, the main portion A ofits area being the thinner and going to make up the body of the boileror drum,

and the auxiliary portion A being preferably about double the thicknessof the former, so as to thoroughly compensate for all weaknessthroughout that area Which is tapped by the multiple holes 6, b, for thetubes B.

It is preferred that one extremity or side edge of the rolled plate Ashall be at one end or edge of the thick auxiliary portion A and thatthe free longitudinal edge of the thinner main body A shall be Weldedthereto at that point, as indicated by the abnormally heavy lines V, inFigs. 1 and 2, but the exact location of this welded joint is arbitrary,so long as the special feature of doing entirely away with lapped orabutting riveted joints or seams is maintained, and a perfectlycylindrical contour be preserved in the interior of the finished boileror drum.

For commercial reasons, involving the purchase in the general market,and use of standard sizes and gages of boiler plates, it is apparentthat our invention will in no wise be departed from should the mainsheet A and the auxiliary portion A of the boiler shell be welded at twopoints WV, as in Fig. 1.

It'will be seen that from the nature and simplicity of this improvementit has been rendered possible and practicable to practice and employ, inone structure of an integral nature, all of the valuable featuressurrounding the needed reinforcement of ordinarily-weakened boilershells at the points where a plurality of tubes may have to enter same,to lessen weight of metal throughout, and also-to conveniently adopt anduse a simple welding process for joining the meeting edges of the shellin lieu of the objectionable riveting methods,

the whole of the advantages herein set forth being accomplished atpractically one-half the cost for material and labor, and the efiiciencyand appearance of the finished boiler at the same time greatly enhanced.

hat we claim and desire to secure by Letters Patent is as follows:

1. The combination in a water tube boiler, of a cylindrical drum madefrom two cylindrical segments of differentthickness, which segments arewelded along their contiguous edges to form a seamless drum, with theinterior surfaces of the segments continuous and flush and in the samecircumference, so that the inside of the drum is smooth, the thickerportion of said drum being perforated and designed to receive the tubessecured in said perforations.

2. The combination in a water tube boiler of a cylindrical drum which isof substantially the same thickness throughout its circumference exceptin that portion which is to receive the tubes; said tube-receivingportion being thicker and in the plane of the remainder of the boilerdrum and united thereto by welding, so that the interior of the boilerdrum is substantially Hush and of uniform diameter and with the thickerpart in continuation with the thinner part and homogeneous therewith,and tubes piercing the thickened portion of the boiler drum,substantially as, andfor the purpose described.

In testimony whereof, we have signed in the presence of the twosubscribing wit- Copies of this patent may be obtained for five centseach, by addressing the Commissioner of Patents. Washington, D. G.

